Anti-depressant effect of curcumin-loaded guanidine-chitosan thermo-sensitive hydrogel by nasal delivery.

Curcumin, a polyphenol compound extracted from the roots of turmeric plants, possesses anti-depressant effect by regulating the levels of neuroendocrine immunological factors. The purpose of this study was to investigate the anti-depressant effect of curcumin through nasal delivery. The results of phase solubility, Fourier transform infrared spectra, Differential scanning calorimetry, X-ray powder diffractometry and 1H NMR spectra assays showed that curcumin/hydroxypropyl-ß-cyclodextrin complex had been obtained. The viscosity of hydrogel increased rapidly at the temperature range of 29-30 °C through the test of rheological property of Guanidine-Chitosan thermo-sensitive hydrogel. And the hydrogel had good mucoadhesion properties. The cumulative release rate of curcumin was 55% in 10 h in vitro drug release test. Curcumin-loaded (14.6, 29.2, or 58.4 µg/kg) thermo-sensitive hydrogel could reduce the immobility time of mice in force swimming test and tail suspension test, while could not increase the independent behavioral activity of mice. In addition, curcumin-loaded (14.6, 29.2, or 58.4 µg/kg) thermo-sensitive hydrogel could increase the concentration of Norepinephrine, Dopamine, 5-Hydroxytryptamine and their metabolites in hippocampus and striatum. In conclusion, thermo-sensitive hydrogel delivery system can be seen as a promising formulation of curcumin for the treatment of depression through nasal delivery.

[Effect of CO2 fertilization on residual concentration of cypermethrin in rhizosphere of C3 and C4 plant].

In order to achieve sustainable economic and environmental development in China, CO2-emission reduction and phytoremediation of polluted soil must be resolved. According to the effect of biological carbon sequestration on rhizosphere microenvironment, we propose that phytoremediation of polluted soil can be enhanced by CO2 fertilization, and hope to provide information for resolving dilemma of CO2-emission reduction and phytoremediation technology. In this study, effects of CO2 fertilization on cypermethrin reduction in rhizosphere of C3-plant (bush bean) and C4-plant (maize) were investigated. Results showed that dry weight of shoot and root of bush bean (C3 plant) was increased by CO2 fertilization. Relative to ambient CO2, dry weight of root was increased by 54.3%, 31.9% and 30.0% in soil added with 0, 20 and 40 mg x kg(-1) cypermethrin respectively. Microbial biomass was increased by CO2 fertilization in rhizosphere soil added with 0 mg x kg(-1) cypermethrin, but negative effect was found in rhizosphere soil added with 20 and 40 mg x kg(-1) cypermethrin. CO2 fertilization slightly affected residual concentration of cypermethrin in rhizosphere soil added with 0 mg x kg(-1) cypermethrin, but significantly decreased residual concentration of cypermethrin as 24.0% and 16.9% in soil added with 20 and 40 mg x kg(-1) relative to ambient CO2. In maize plant, however, plant growth, microbial biomass and residual cypermethrin concentration in rhizosphere was slightly affected by CO2 fertilization, and even negative effect was observed. This study indicated that CO2 fertilization decreases the residual concentration of cypermethrin in rhizosphere of C3-plant, and it is possible to enhance phytoremediation of organic-polluted soil by C3-plant through CO2 fertilization. However, further study is needed for C4-plant.